E0724: The home page outside the root layouts

With no pages/_layout.vuka.html, each route group at the top of pages/ may have a _layout.vuka.html of its own: the document of the pages inside it, a root layout. The site's sections then each have their own document, and the home page, /, belongs to one of them. A home page outside every group with a layout would render with no document of the site's at all.

Wrong

pages/
  index.vuka.html              Home — /, under no root layout
  (site)/
    _layout.vuka.html          Site: the document of the site's pages
    about.vuka.html            About — /about
  (shop)/
    _layout.vuka.html          Shop: the document of the shop's pages
    cart.vuka.html             Cart — /cart

Right

pages/
  (site)/
    _layout.vuka.html          Site: the document of the site's pages
    index.vuka.html            Home — /
    about.vuka.html            About — /about
  (shop)/
    _layout.vuka.html          Shop: the document of the shop's pages
    cart.vuka.html             Cart — /cart